TWI544180B - Control Method of Circulation Rate of Fluidized Bed in Inner - Google Patents

Description

Method for controlling circulation rate of fluidized bed of internal general formula 【0001】

The present invention relates to a control method, and more particularly to a control method for dynamically controlling the particle circulation rate of a fluidized bed of the internal type.

【0002】

The large amount of carbon dioxide is emitted into the atmosphere, which has caused environmental problems of global warming in the long run, and the demand for fossil fuels has not been effectively solved. The development of carbon dioxide capture and storage (CCS) is currently One of the important methods known to reduce carbon dioxide emissions in large quantities is known. This method has also been recognized by the United Nations Intergovernmental Panel on Climate Change (IPCC) as an effective greenhouse gas reduction mechanism.

[0003]

According to the fuel-converted thermoelectric method, today's carbon dioxide capture technology can be distinguished as post-combustion capture, pre-combustion capture, oxyfuel combustion capture, and chemical loop combustion procedures. The looping combustion process can be attributed to an alternative oxyfuel combustion field. Among them, the use of the internal fluidized bed to perform the chemical loop program is a relatively promising technology. This technology has low exhaust pollution and high power generation efficiency characteristics, and has been recognized as a great potential in the world.

[0004]

Role-based chemical loop principle allow the fuel to enter the "fuel reactor" (fuel reactor), the reduction reaction at 900-950 ^o C and added of an oxygen carrier (Me _x O _y), so oxidation of the fuel to CO ₂ and H ₂ O, Me _x O _y is reduced to Me _x O _y-1 . The reduced oxygen carrier Me _x O _y-1 is then sent to an air reactor, oxidized with oxygen at 500-700 ^o C, and converted to Me _x O _y to form a loop ( Looping). Accordingly, as the oxygen carrier circulates in the chemical loop process, carbon dioxide and steam can be generated in the fuel reactor, and after the steam is separated by the condensing unit, carbon dioxide having a purity higher than 95% can be obtained and obtained in the air reactor. Thermal energy; the carbon dioxide produced can be directly sealed or reused, and has the advantages of low cost and high energy efficiency.

[0005]

The internal fluidized bed system integrates a plurality of circulating fluidized beds and a particle conveying pipeline thereof, and a plurality of fluidized beds constitute a single bed body, and the particles are transported between the beds by different fluidization speeds. The various reaction procedures required. During its operation, the fluidized particles descend in the dense bed and enter the lean bed through the orifice at the bottom; the particles rise in the sparse bed and pass over the top of the crucible ( Weir) enters another dense bed and repeats like this. The fluidized bed of the internal fluidized bed has the advantages of a circulating fluidized bed, but has no complicated mechanical structure, such as a particle conveying pipeline, and thus has a high particle circulation rate and less particle loss, which can reduce construction and Operating costs, while operating efficiency is higher than the traditional fluidized bed.

[0006]

However, although the internal fluidized bed has a large number of transfer lines in the structure, there is currently no effective technique for dynamically controlling the circulation rate of the internal particle fluid. Since the particles enter the internal fluidized bed, the rate of reaction in each bed interval can only depend on the system default, that is, limited by the standard specifications, the user can only change the total amount of particles input and The fluid velocity does not meet the industrial demand. In particular, it is impossible to effectively adjust the particle circulation rate linearly to find the optimal circulation rate. In addition, only changing the total particle volume and fluid velocity also has a growth bottleneck. The function of the fluidized bed of the internal formula is thoroughly exerted.

【0007】

The main object of the present invention is to provide a dynamic control method for the circulation rate of a fluidized bed of the general formula, which can simultaneously adjust a plurality of Circulation Rate of Solids (CSR) in a fluidized bed of the internal general flow. Parameters, and get the speed increase effect that cannot be achieved by changing a single parameter.

[0008]

A further object of the present invention is to provide a dynamic control method for the circulation rate of a fluidized bed of the present general formula, which can adjust the particle circulation rate in a timely manner to meet the demand of a variable load.

【0009】

Another object of the present invention is to provide a dynamic control method for the circulation rate of a fluidized bed of the internal general formula, which can adjust the particle circulation rate to a suitable degree depending on the nature of the particles, and avoid the excessively fast circulation rate, resulting in a single particle. The residence time of the bed area is too short, reducing the possibility that the particles have not completed the reaction and left.

[0010]

Another object of the present invention is to provide a dynamic control method for a fluidized bed circulation rate of a general formula, wherein the controlled fluidized bed can be applied and developed for a chemical loop program, and can be combined with various reactions. Under the advantage of the device, the efficiency of the chemical loop program is optimized to the best.

[0011]

A further object of the present invention is to provide a dynamic control method for the circulation rate of a fluidized bed of the internal type, which can design a gate for the orifice on the body to realize the goal of dynamic control without being preset. The height of the mouth and the size of the cross-sectional area.

[0012]

In order to achieve the above object, the present invention discloses a dynamic control method for a fluidized bed circulation rate of a general formula, the internal fluidized bed system comprising a plurality of bed zones, wherein the bed zones are respectively a carcass For spacing, some of the enthalpy systems have at least one orifice for at least one particle fluid to pass therethrough, characterized in that the control method dynamically controls the particle fluid to the internal formula using at least one of the group consisting of the following steps; The circulation rate in the fluidized bed: adjusting the height difference between the orifice and one of the bottom surfaces of the bed; adjusting the cross-sectional area of the orifice; and adjusting the height of the body.

10A bed area
10B bed area
10C bed area
10D bed area
20A carcass
20B carcass
20C carcass
20D carcass
22 orifice
30 carcass
31 bed area
310 bottom
32 orifice
40 carcass
42 orifice
44 gate
H height difference

[0013]

1A is a perspective view showing the internal structure of a fluidized bed of a general formula using a four-bed area according to a preferred embodiment of the present invention;
1B is a top plan view showing the internal structure of a fluidized bed of a general formula using a four-bed area according to a preferred embodiment of the present invention;
1C is a schematic view showing the flow direction of a fluid particle of a fluidized bed of a general formula using a four-bed region according to a preferred embodiment of the present invention;
Figure 2 is a schematic view showing the structural change of adjusting the height of the orifice at the height of the body according to a preferred embodiment of the present invention;
3A, 3B: It is a test result diagram of the present invention to indicate the influence of the change in height difference;
4A is a schematic view showing a structural change of a gate using a preferred embodiment of the present invention;
Figure 4B is a schematic view showing the structure change of the gate using another preferred embodiment of the present invention;
5A~5C: It is a test result diagram of the present invention, which is used to indicate the influence of the change of the cross-sectional area of the orifice; and 6A, 6B: it is a test result diagram of the present invention, which is used to represent the bed. The effect of heavy changes on the cycle rate of the particles;

[0014]

For a better understanding and understanding of the features and advantages of the present invention, the preferred embodiments and the detailed description are described as follows:

[0015]

The dynamic control method of the fluidized bed circulation rate of the present invention is operated in a fluidized bed of the general formula. Please refer to FIG. 1A and FIG. 1B, which is a fluidized system composed of four beds. The bed is an operational target in a preferred embodiment of the invention. As shown in the figure, the internal structure of the fluidized bed of the general formula comprises a plurality of bed zones 10A, 10B, 10C, 10D, and the bed zones 10A, 10B, 10C, 10D are respectively formed by carcass 20A, 20B, 20C. 20D is the interval. Some of the cartridges, such as the cartridges 20B, 20D in the preferred embodiment, have at least one orifice 22 for at least one particle fluid to pass through; and another portion of the cartridges, such as the cartridges 20A, 20C, are not provided. In the orifice, the height of the carcass without the orifice is lower than that of the carcass with the orifice, and thus the particle fluid can be passed over it to reach the adjacent bed zone. The direction and path of particle fluid flow can be referred to the indication in Figure 1C.

[0016]

In principle, a fluidized bed of the general formula integrates a circulating fluidized bed and a particle transport line thereof, and the bed zones of the plurality of fluidized beds are adjacent only to the carcass, and by different fluidization speeds The particles are transported between the various bed zones to complete the various reaction procedures required. However, in the general internal fluidized bed, the particle circulation rate control is very limited, especially in the process of fluid flow in the bed after the fluidization of the particle, there is no effective method to regulate, so the present invention proposes a method dynamic control method The particle circulation rate based on the particle in the fluidized bed of the internal type is increased or decreased by a plurality of variables, and the calculation formula is Equation 1:


(Formula 1) CSR(g/s) = C _D × A ₀ × [2 × ρ _s × (1 - ε _mf ) × ΔP] ^0.5


Wherein C _D is the emission coefficient, A ₀ is the orifice cross-sectional area, ρ _s is the particle density, ε _mf is the porosity in the bed area at the minimum fluidization, and ΔP is the pressure difference across the orifice. Accordingly, the present invention changes the operating conditions of the fluidized bed of the internal fluid in a number of ways such that the above-described particle circulation rate is altered to be adjusted to the desired preferred rate.

[0017]

The dynamic control method of the present invention is based on the concept of multivariate control. In order to adjust various parameters, the following steps can be selectively performed: (1) adjusting the height difference between the aperture and the bottom surface of the bed area; (2) Adjusting the cross-sectional area of the orifice; (3) adjusting the height of the body; (4) adjusting the fluid entry rate of a fluid entering the module; (5) adjusting the amount of particles of the particle fluid in the fluidized bed of the internal fluid And (6) adjusting the particle species of the particle fluid in the fluidized bed of the internal formula. The present invention is not limited to adjusting only a single parameter, and the visual control amplitude is adjusted by more than one parameter, so that multiple steps can be performed simultaneously in execution to substantially increase the variation of the particle circulation rate by using the sum of the effects thereof.

[0018]

In the step of (1) adjusting the height of the opening in the body, the body can be connected to a lifting module. The lifting module is not limited to a type, and can be disposed above the body to be The traction is raised, or placed under the body to push up, or it may be an electromagnet type or a magnetic substance that is placed on the body or the body will be sucked up or down. Referring to FIG. 2, when the body 30 is subjected to a height change with respect to the bottom surface 310 of the bed 31 by the action of the lifting module (not shown), the opening 32 and the bottom surface 310 of the bed 31 are The height difference H also changes. The principle of this step is that the flow of particles near the orifice is caused by different bed zones, such as the pressure difference between the dense bed and the sparse bed, or the difference in bed density. As the gas velocity in the sparse bed area increases, the bed height increases and the bed density decreases. Therefore, the greater the pressure difference near the orifice leads to the increase of the particle circulation rate. Therefore, it is possible to change the particle circulation rate by changing the aforementioned height difference H and further utilizing the pressure difference of different heights.

[0019]

In a test case, please refer to Figures 3A-3B, where the orifice diameter is 1.5 cm and 3.0 cm, respectively, at a particle fluid weight of 17.0 kg and a bed fluid velocity U/U _mf = 4.5. , a comparison of changes in particle circulation rate. When the height difference H is 4 cm and 6 cm, the particle circulation rate is 66.28 and 81.28 g/s, respectively. When the height difference H is increased from 4 cm to 6 cm, the particle circulation rate will increase, and As the fluid velocity U/U _mf in the bed zone increases, the particle circulation rate also increases. However, when the height difference H is increased to 8 cm and compared with the particle circulation rate at 6 cm, the difference between the two is small, and it can be known that the adjustment effect provided by the single step has an upper limit, and to obtain a larger The adjustment effect needs to be carried out simultaneously with other steps.

[0020]

In the step of (2) adjusting the cross-sectional area of the orifice, a gate may be provided at the orifice, and the cross-sectional area of the orifice is linearly changed by the gradual opening and the stepwise closing of the gate. 4A is a manner in which one of the gates is designed to provide a steerable gate 44 at the aperture 42 of the body 40, thereby changing the cross-sectional area of the aperture 42. Based on this gate 44, the original size of the aperture 42 can be designed to be relatively wide, and the gate 44 can be used to flexibly adjust the cross-sectional area of the aperture 42. The design of the gate 44 is also not limited to being closed up and down. For example, in order to reduce the height difference H of the gate in the switching process, it may be designed to be closed in the left-right direction. Fig. 4B is a form of another type of gate and orifice that is attached to the body 40 having a plurality of apertures 42, and the gate 44 progressively opens or closes a portion of the apertures 42 during the switching process. The distribution of the orifices 42 is not limited to being uniformly arranged, and may be gradually changed in accordance with the height of the body 40 in a regular manner, so that the cross-sectional area is obtained when the gate 44 is moved up and down at a constant speed or moved left and right. Corresponding to the effect of progressive changes.

[0021]

In a test case, please refer to the 5A~5C figure, when the height difference H is 4 cm, 6 cm and 8.0 cm, respectively, the particle fluid weight is 17.0 kg and the bed fluid velocity U/U _mf = 4.5. Under the conditions, the change of the particle circulation rate is compared. Where the diameter of the circular orifice is 1.5, 3.0 and 6.0 cm, the particle circulation rates are 66.28, 219.23 and 284.16 g/s (H = 4 cm), 81.28, 243.93 and 560.32 g/s (H = 6 cm). ), 82.77, 228.00 and 479.74 g/s (H = 8 cm). It can be proved that as the cross-sectional area of the orifice increases, the particle circulation rate tends to increase.

[0022]

In the step of (3) adjusting the height of the body, the height of the body not provided with the opening can be adjusted by using the above-mentioned lifting module. The principle is that the helium system without orifices is used to allow the particle fluid to pass over it to reach the adjacent bed zone, so that when the height of the carcass is reduced, more of the particle fluid can naturally move in the bed zone.

[0023]

The step (4) of adjusting the fluid entry rate of a fluid into the module is based on the basic mechanism of the fluidized bed, that is, the fluid consisting of a gas or a liquid is passed under the bed provided with the solid particles. If the fluid velocity is low, the particles do not move and are in a fixed bed state; and if the fluid velocity is increased to be greater than the minimum fluidization velocity of the particles, the particles are suspended from each other and move with the fluid. In this context, the fluid entering the module is provided by the fluid below the bed zone, and more fluid and particles are moved in the bed section by increasing the fluid velocity. The foregoing Figures 3A-3B and 5A-5C demonstrate that the particle circulation rate increases as the fluid velocity U/U _mf in the bed zone is increased.

[0024]

And in the step of (5) adjusting the particle amount of the particle fluid in the fluidized bed of the internal fluid and (6) adjusting the particle type of the particle fluid in the fluidized bed of the internal fluid, the present invention is The inner fluidized bed is connected to a feed module. The feed module can provide additional particles into the circulation, or extract a portion of the particles of the fluidized bed of the internal formula, thereby changing the number of particles in the fluidized bed of the internal formula, or changing the composition of the particles, resulting in the particles The total weight and stack height vary.

[0025]

Taking gas as a fluid as an example, please refer to Figures 6A to 6B, which are the test results of the effect of bed weight on particle circulation rate. In Figures 6A to 6B, the particle circulation rates are compared when the diameter of the orifice is 3 cm and 6 cm, and the height difference H is 6 cm and the bed weight is 16, 16.5, 17.0 and 17.5 kg. According to the test results, it can be proved that the particle circulation rate will increase with the increase of the bed weight, which is mainly because when the bed weight increases, the height of the particles stacked on the bed area will also increase, and the effect of the bubble combination of the fluid is obvious. . As the bubble reaches the surface of the bed, the diameter increases, the strength of the bubble rises as it cleaves, and its strength is sufficient to allow more particles to pass over the carcass, thus causing an increase in the particle circulation rate.

[0026]

In summary, the various steps disclosed in the present invention have the benefit of speed increase, but it is considered that there are bottlenecks in the increase of the particle circulation rate in individual steps, so to achieve the maximum particle circulation rate, it is necessary to simultaneously pass through a plurality of Steps are adjusted to obtain the sum effect of the gain. On the other hand, the reaction time required for different kinds of particles in the bed interval is not the same. If the particle circulation rate is too fast, that is, the residence time of the particles in any bed area is too short, the reaction may not be completed. When forced to leave, the purpose of completing the chemical loop cannot be achieved. Therefore, although the present invention can greatly increase the particle circulation rate, another important significance is that the dynamic control can be arbitrarily performed within the maximum particle circulation rate to make the internal fluidization After the bed is started, the particle circulation rate curve can be converged to the optimal particle circulation rate at the fastest speed, and the load demand is varied as needed, which has high practical value.

[0027]

The above is only the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and the variations, modifications, and modifications of the shapes, structures, features, and spirits described in the claims of the present invention. All should be included in the scope of the patent application of the present invention.

10A bed area

10B bed area

10C bed area

10D bed area

20A carcass

20B carcass

20C carcass

20D carcass

22 orifice

Claims (8)

[Item 1] A dynamic control method for a fluidized bed circulation rate of a general formula, the internal fluidized bed system comprising a plurality of bed zones, wherein the bed zones are respectively separated by a corpus callosum, and some of the enthalpy systems have at least An orifice for passage of at least one particulate fluid, characterized in that the control method dynamically controls the circulation rate of the particulate fluid within the fluidized bed of the internal fluid using at least one of the group consisting of:
Adjusting a height difference between the orifice and a bottom surface of the bed zone;
Adjusting the cross-sectional area of the aperture; and adjusting the height of the body. [Item 2] The method for dynamically controlling the circulation rate of a fluidized bed according to the first aspect of the invention, wherein the lower portions of the bed portions each have a fluid inlet module for conveying the fluid upward. [Item 3] The method for dynamically controlling the circulation rate of a fluidized bed of the internal formula as described in claim 2, further comprising a step of dynamically controlling the circulation rate of the particle fluid in the fluidized bed of the internal formula: adjusting the fluid The fluid rate entering the module. [Item 4] The method for dynamically controlling the circulation rate of a fluidized bed of the present invention as described in claim 1, wherein the fluidized bed of the internal fluid is connected to at least one feed module. [Item 5] The method for dynamically controlling the circulation rate of a fluidized bed of the internal formula as described in claim 4, further comprising a step of dynamically controlling the circulation rate of the particle fluid in the fluidized bed of the internal formula: using the The material module adjusts the amount of particles of the particle fluid in the fluidized bed of the internal formula. [Item 6] The method for dynamically controlling the circulation rate of a fluidized bed of the internal formula as described in claim 4, further comprising a step of dynamically controlling the circulation rate of the particle fluid in the fluidized bed of the internal formula: using the The material module adjusts the particle species of the particle fluid to the fluidized bed of the internal fluid. [Item 7] The method for dynamically controlling the circulation rate of a fluidized bed of the internal formula according to claim 1, wherein in the step of adjusting the height difference between the orifice and the bottom surface of the bed region, the body and the body are The lifting modules are connected. [Item 8] The method for dynamically controlling the circulation rate of a fluidized bed according to the first aspect of the invention, wherein in the step of adjusting the cross-sectional area of the orifice, a gate is disposed in the orifice.